Why use EPDs for Genetic Improvement ?
By Dr Sara Via
Some of the articles in previous folders have touched on how EPDs can be used in breeding programs. The articles here continue and extend this discussion, with additional information about how EPDs and other factors affect the rate of genetic improvement.
Articles: The following articles are graded according to their technical complexity.
One star * = simple
Two stars ** = moderate
Three stars *** = technical
General
1_Application of Selection Concepts for Genetic Improvement. National Swine Improvement Federation, Fact Sheet #9. This article discusses the basic theory of using artificial selection to improve livestock, considering strength of selection (what fraction of herd is allowed to breed vs. being culled), accuracy of EPD and so on.**
Cattle
2_ Using Expected Progeny Differences, Dr. Darrh Bullock, Department of Animal Science, University of Kentucky. Good discussion of what EPDs can and cannot do, and how to use them in a selection program. There is also a good discussion of how to use the estimates of accuracy for each EPD in making breeding decisions.*
3_ Strategies for use of Expected Progeny Differences in Cattle, Dr. Pete Anderson, Extension Cattle Specialist, University of Minnesota. The first 3 pages are a good review of EPDs, the rest of the paper is focused on how EPDs are used in a selection program. *
4_ Interpretation and Utilization of Expected Progeny Differences. Dr. J.M. Rumph, Department of Animal Science, University of Montana. Ch. 9 in the Beef Sire Selection Manual. Good basic review of selection programs, a little heavy on descriptions of different cattle traits, but very good discussion of heritability (how much of the variance that you can see in a given trait within the herd is due to genetic causes) and genetic correlations (to what extent do the same genes affect different traits). This leads into a discussion of multiple traits and why it is crucial to decide the most important traits before you start imposing selection (selection on several traits at the same time can produce opposing results and a net gain of nothing).***
5_Visual and Phenotypic Evaluation of Bulls. Dr. Dan Moser, Department of Animal Science, Kansas State University. Chapter 12 in the Beef Sire Selection Manual. This is a good explanation of why using EPDs is better than using visual evaluation (even in combination with EPDs). However, Dr. Moser also considers the importance of visual evaluation for traits not included in EPD analysis (such as health, disposition, difficulty giving birth or producing milk) that might be economically important.***
Swine
6_Using Expected Progeny Differences in Swine Selection, Dr. M. Todd See, Department of Animal Science, North Carolina State University. Very nice review of what EPDs are, and some fairly simple descriptions of their use*
7_ Selection Programs for Seed stock Producers, NSIF Fact Sheet #15. Describes how to define selection goals, why performance testing is desirable, and how to use EPDs in a selection program.*
Sheep
8_Using EPDs to Select Sheep, National Sheep Improvement Program (NSIP), Fact Sheet #6. Simple examples of how EPD values can be used to choose which animals to breed. *
9_How to Use EPDs to Select and Cull Sheep from Your Flock, NSIP Fact Sheet #7. Continues explanation of using EPDs to breed, with emphasis on determining which animals to cull (remove from breeding program).*
10_How to Use EPDs to Purchase Breeding Animals, NSIP Fact Sheet #8. Continuation of the explanation of using EPDs, with emphasis on how to use them when purchasing animals*